error: unused `async` for function with no await statements
  --> $DIR/unused_async.rs:45:5
   |
LL |     async fn f3() {}
   |     ^^^^^^^^^^^^^^^^
   |
   = help: consider removing the `async` from this function
   = note: `-D clippy::unused-async` implied by `-D warnings`

error: unused `async` for function with no await statements
  --> $DIR/unused_async.rs:57:1
   |
LL | / async fn foo() -> i32 {
LL | |     4
LL | | }
   | |_^
   |
   = help: consider removing the `async` from this function

error: unused `async` for function with no await statements
  --> $DIR/unused_async.rs:13:5
   |
LL | /     async fn async_block_await() {
LL | |         async {
LL | |             ready(()).await;
LL | |         };
LL | |     }
   | |_____^
   |
   = help: consider removing the `async` from this function
note: `await` used in an async block, which does not require the enclosing function to be `async`
  --> $DIR/unused_async.rs:15:23
   |
LL |             ready(()).await;
   |                       ^^^^^

error: unused `async` for function with no await statements
  --> $DIR/unused_async.rs:68:5
   |
LL | /     async fn unused(&self) -> i32 {
LL | |         1
LL | |     }
   | |_____^
   |
   = help: consider removing the `async` from this function

error: aborting due to 4 previous errors